A 529 Plan is a tax-advantaged post-secondary education investing plan. In some states, the plan can carry State Tax advantages by using the state sponsored plan. In Massachusetts, there are no state tax advantages to utilizing the Ufund program, so all 529 programs are on equal footing.
Tax-advantage means that the investments grow in a tax-deferred basis and can be spent on qualified post-secondary education expenses in a tax-free manner. The initial investments are from after-tax sources.